Circuit breaker



May 2, 1939. J. G. JACKSON ET AL CIRCUIT BREAKER Filed 001;. 31; 1935 3 Sheets-Sheet l INVENTORS.

R nhold Mae ATTORNEY.

y 2, 1939- J. G! JACKSON Er AL 2,156,762

CIRCUIT BREAKER Filed Oct. 51, 1935 3 Sheets-Sheet 2 E-E- A.

INVENTORS. 0)? 6': v 7'ac%son,

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77 4M Jjz/fl ATTORNEY.

Patented May 2, 1939 UNITED STATES 2,156,762 omom'r BREAKER John G. Jackson and Reinhold Mueller, Detroit,

Mich, assignors to Square D Company, Detroit, Mich, a corporation of Michigan ApplicationOctober 31, 1935, Serial No. 47,526

16 Claims. (Cl. 200-116) This invention relates to automatic electric circuit breakers and has for its object the provision of an improved group circuit breaker.

Another object of this invention is to providea scalable circuit breaker having a plurality of individual mechanisms, certain parts of which are made electrically common by a common bus.

Another object of this invention is to provide an electric circuit breaker having a plurality of individual mechanisms with a common bus sup-v porting the current responsive latches for the mechanisms.

Another object of this invention is to provide an improved and economical form of circuit breaker having a plurality of individual mechanisms and common mounting features.

Another object of this invention is to provide an improved and economical form of circuit breaker mechanism.

Another object of this invention is to provide an improved form of circuit breaker apparatus including an outer box enclosing a sealable circuit breaker having improved features of sim plicity and economy.

Other objects and features of this invention will be readily apparent to those skilled in the art from the following specification and the appended drawings illustrating certain preferred embodiments of the invention in which:

80 Figure 1 is a top plan view of a circuit breaker apparatus according to the present invention with the outer cover broken away.

Figure 2 is a vertical sectional view on the line II-H of Figure 1.

25 Figure 3 is a fragmentary horizontal sectional view on the line III-41! of Figure l with the parts in the on position. a

Figure 4 is a fragmentary view similar to Figure 3 showing the parts in automatic trip position.

40 Figure 5 is a fragmentary vertical sectional view taken on the line V-V of Figure 1.

Figure 6 is a sectional view taken on the line VI-VI of Figure 5.

Figure 7 is a view similar to Figure 3 showing 45 the parts in manual trip position.

Figure 8 is a view similar to Figure 3 showing the parts in a resetting position.

The circuit breaker apparatus illustrated in the drawings comprises a sheet metal enclosing box I 5o having an openable cover 2 hingedly or otherwise mounted thereon. This box may be equipped with the usual knockouts, cover latch and similar features as is conventional in the art. Within this outer box is mounted one or more sealable circuit breaker units. In the specific illustration in the drawings two units are shown. It is readily understood that any number of these units may be mounted in a single enclosing box or cabinet and as they are duplicates only a single unit will be hereinafter described. a 5 The circuit breaker embodies a base 3 having a plurality of individual compartments 4. In each of these compartments is disposed an individual circuit breaker mechanism. Extending across the base and common to the individual compart- 10 giants and mechanisms is a bus 5 secured to the ase by means'of studs 6 threaded into metallic inserts l in the base 3. In the specific embodiment of the invention illustrated, the bus 5 is extended at one end of the base to a position. exterior thereof as at 8 and is there provided with a terminal washer 9 and stud H. A portion of the base adjacent to each compartment is formed to provide a shelf 12 upon which is secured the conductor l3. This conductor I3 is placed over a 20 metallic insert M the end of which is then spun or pressed over the conductor to hold it rigidly in place. The insert it is interiorly threaded and receives the terminal stud IS. A wall of the base adjacent the shelf I2 is provided with an opening 25 through which the conductor I3 is extended into the interior of the compartment to form the stationary contact I6.

A bracket I1 is rigidly secured to the base as by means of a stud 18. To the bracket n is rigidly mounted a supporting shaft I9. Upon the shaft I9 is pivotally supported a U-shaped carrier 2| having a latch arm 22 rigid therewith. A bimetallic strip 23 is rigidly mounted on the bus 5 as by welding or riveting or in any other manner 3 and is provided adjacent its free end with a latching surface engaging the latch arm 22.

A U-shaped contact arm 24 carrying a movable contact 25 is pivotally mounted as at on the carrier 2| by the engagement of the tongues on Y the free ends of the legs of the U-shaped contact arm with the openings in the free ends of the legs of the U-shaped carrier. A flexible lead 20 connects the free end of bimetal 23 with the movable The shaft I9 is provided with a reduced portion 26 interjacent its ends receiving a slot 21 in the lower portion of an operating push button 28, provided at its exterior end with an insulating portion 29. An overcenter operating spring 3| interconnects the push button 28 and the contact arm 24 and is disposed between the legs of the arm. The. push button 28 is provided with a cutout portion 32 receiving the carrier 2| in its automatic trip position as shown in Figure 4. A flange or lug 33 is provided on the push button 28 upon one side of the slot 21 in position to engage a leg of the carrier 2| in a manner to be hereinafter described.

The operation of the individual circuit breaker mechanism will now be described. The parts shown in Figure 3 are in their normal closed circuit position. Upon the occurrence of an overload and bimetal 23 will become heated and warp in a direction to release the latch arm 22 whereupon the parts will rotate to the position shown in Figure 4 under the influence of the operating spring 3|. The carrier 2| when released rotates clockwise and moves the pivot 30 through the line of operation of the spring 3| whereupon the contact arm 24 is rotated by the spring into the position shown. In the resetting operation as illustrated in Figure 8 the end 29 of the push button 28 is manually pulled outward whereupon the flange or lug 33 engages the leg of the carrier 2| and rotates it back into latched engagement with the bimetal 23. In this movement of the carrier the pivot 30 stays below the line of operation of the spring 3| so that when the latching is completed the parts are in their normal position as shown in Figure 7. To again move the contacts into engaged position the push but ton is depressed moving the spring 3| through the pivot 30 whereupon the contact 25 is snapped into engagement with the stationary contact Hi.

The operation from on position of Figure 3 to the manual off position of Figure 7 is obtained by pulling outwardly on the push button handle 29 whereupon the spring 3| is moved above the pivot 30 and the contact 25 is moved to its off position as shown in Figure 7.

The walls between the adjacent compartments are cut away at the level of the bus to provide for insertion of t e bus at the back and further to provide communication between the compartments to permit the gases generated by the separation of any pair of contacts to be expelled throughout the entire circuit breaker interior, thus rendering less necessary any vent to the outer air. It is readily understood that these walls may be entirely omitted as they are in no way essential to the construction of the circuit breaker.

A fibre plate 34 is disposed adjacent the back of the base and is held in place by means of a metallic plate 35 rigidly secured to the base in sealable relation by means of rivets 36. The circuit breaker units may be mounted in their outer enclosing box or .cabinet by means of studs 3'! connecting the metallic plates of the enclosing box.

The extension 8 of the bus 5 to the exterior of the circuit breaker enclosure may be utilized as a bus tap or as a main terminal for the breaker. When used as a main terminal the individual mechanisms will then function as individual breakers-to the separate circuits. When used as a bus tap one of the individual mechanisms will function as a main circuit breaker leading to the bus 5 which in turn will feed through the other individual mechanisms to the individual circuits. In this arrangement the circuits fed through the load breakers will thus be provided with both main and branch circuit protection having at all times two circuit breakers in series with any short which may occur. However, when the extension 8 is used as a bus tap, feeding therefrom will be only through the main breaker. In many instances this is undesirable and'in these cases the bus 5 may be cut off within the circuit'breaker 35 to the back interior and access prevented either by use of a base having the complete wall at both ends or by means of a tab on the fibre plate 34 extending into the opening through which bus 5 was extended. In this case the feeding to the branch circuits will always be through two circuit breaker mechanisms whereof one provides main protection to all the branch circuits and the other individual mechanisms provide branch protection for their individual circuits.

In the appended claims the terms box and cover are to be construed to include cabinet" and .door respectively.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto as many variations will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpretation Within the terms of the following claims.

What is claimed is:

1. An electric circuit breaker comprising a plurality of individual mechanisms including separable contacts and means for automatically separating said contacts in response to overload, said means including a bimetallic latch, a common bus for said mechanisms, one end of said latches being rigidly mounted on said bus in conducting relation thereto, and means connecting the other end of each of said latches to a contact of its respective mechanism.

2. An electric circuit breaker comprising a plurality of individual mechanisms including separable contacts and means for automatically separating said contacts in response to overload, said means including a bimetallic latch, a common bus for said mechanisms, one end of said latches said bus in conducting relation thereto, and means connecting the other ends of said latches to a contact of their respective mechanisms, said mechanisms and bus being mounted in a sealable enclosure.

3. An electric circuit breaker comprising a unitary base having a plurality of compartments therein, a circuit breaker mechanism mounted in each of said compartments and comprising relative movable contacts, manual means for separating said contacts and automatic means for separating said contacts in response to overload, a bus bar connected to said base and extending across said compartments, and means connecting one contact of each mechanism to said bus bar whereby they are electrically common. and a cover sealably attached to said base and enclosing said mechanisms and bus bar.

4. An electric circuit breaker comprising a unitary base having a plurality of compartments therein, a circuit breaker mechanism mounted in each of said compartments and comprising relative movable contacts, manual means for separating said contacts and automatic means for separating said contacts in response to overload, a bus bar connected to said base and extending across said compartments, and a cover attachable to said base to form a sealable enclosure for said mechanisms and bus bar.

5. An electric circuit breaker comprising a base having a plurality of compartments therein, a circuit breaker mechanism mounted in each of said compartments and comprising relative movable contacts, manual means for separating said contacts and automatic means for separating said contacts in response to overload, said automatic means including a bimetallic latch, a bus connected to said base and extending across said compartments, one end of said latches being rigidly mounted on said bus in conducting relation thereto and flexible leads interconnecting the opposite ends of the latches with one contact of their respective mechanisms.

6. An electric circuit breaker comprising a sealable enclosure having a plurality of compartments formed by insulating formations common thereto, a plurality of individual mechanisms supported within the compartments of said enclosure and including stationary and movable contacts and manual and automatic means for separating said contacts, a common bus bar supported within said enclosure by means including said insulating formations and means electrically interconnecting said bus bar and said movable contacts.

'7. An electric circuit breaker comprising a sealable enclosure having a plurality of compartments formed by insulating formations common thereto, individual circuit breaker mechanisms mounted in said compartments of said enclosure and including separable contacts, manual means for separating said contacts and automatic means for separating said contacts in response to overload, said automatic means including a current responsive latch, a bus connnon to said mechanisms within said enclosure, means connecting one end of said latches to said bus and means connecting the opposite ends of said latches to one contactpf their respective mechanisms.

8. In an electric circuit breaker, a base, a carrier pivoted on said base, a contact carrying arm pivoted on said carrier, a current responsive latch for said carrier, an operating push button, an overcenter spring interconnecting said arm and push button, means for guiding the reciprocal movement of said push button, means for limiting the extreme positions of said push buttons, said push button moving the spring past said arm pivot for manual operation, said carrier moving the arm pivot past said spring when released by said latch.

9. In an electric circuit breaker, a base, a carrier pivoted on said base, a contact carrying arm pivoted on said carrier, a current responsive latch for said carrier, an operating push button, an overcenter spring interconnecting said arm and push button, means for guiding the reciprocal movement of said push button, means for limiting the extreme positions of said push buttons, said push button moving the spring past said arm pivot for manual operation, said carrier moving the arm pivot past said spring when released by said latch, and an abutment on said push button engaging said released carrier to rotate it back into latched position.

10. In an electric circuit breaker, a base, a carrier pivoted on said base, a contact carrying arm pivoted on said carrier, a current responsive latch for said carrier, an operating push button, an overcenter spring interconnecting said arm and push button, means for limiting the extreme positions of said push button, said push button moving the spring past said arm pivot for manual operation, said carrier moving the arm pivot past said spring when'released by said latch, the means limiting the forward position of said push button engaging said released carrier to rotate it back into latched position upon movement of said push button to normal of! position after an automatic trip.

11. An electric circuit breaker comprising a sealable enclosure including a base, a shaft suptop of ported by said base, a carrier pivotally mounted on said shaft, a current responsive latch for said carrier, a contact carrying arm pivoted on said carrier, an operating push button having an elongated slot receiving said shaft and a spring interconnecting said arm and push button, the top of said slot limiting the interior positions of the push button, and a lug on said push button in the path of said carrier for limiting its exterior position.

12. An electric circuit breaker comprising a scalable enclosure including a base, a shaft supported by said base, a carrier pivotally mounted on said shaft, a current responsive latch for said carrier, 9, contact carrying arm pivoted on said carrier, 'an operating push button having an elongated slot receiving said shaft and a spring interconnecting said arm and push button, the said slot limiting the interior positions of the push button, and a lug on said push button in the path of said carrier for limiting the exterior position, said push button moving the spring past said arm pivot for manual operation, said carrier moving the arm pivot past said spring when released by said latch, said lug engaging the released carrier to rotate it back into latched position upon manual movement of said push button to normal off" position after an automatic trip. 13. In an electric circuit breaker, a base, a carrier pivotally mounted on said base, a contact carrying arm pivoted on said carrier, a current responsive, bimetallic latch for said carrier, one endof said bimetal being rigidly mounted on an electrical conductor, a flexible lead connecting the free end of said bimetal to the contact on said arm, an operating push button mounted for longitudinal movement, and an overcenter spring operatively interconnecting said push button and arm.

14. An electric circuit breaker comprising a sealable enclosure having a plurality of compartments formed by insulating formations common thereto, a plurality of individual mechanisms supported within the compartments of said enclosure and including stationary and movable contacts and manual and automatic means for separating said contacts, a common bus bar supported within said enclosure by means including said insulating formations, and means electrically interconnecting said bus bar and said movable contacts, said interconnecting means including a thermally warping bimetallic latch and a flexible lead permitting free unlatching movement of the bimetal and free manual movement of the movable contact.

15. An electric circuit breaker comprising a sealable enclosure having a plurality of compartments formed by insulating formations common thereto, individual circuit breaker mechanisms mounted in said compartments of said enclosure and including separable contacts, manual means for separating said contacts and automatic means for separating said contacts in response to overload, said automatic means including a current responsive latch, a bus common to said mechanism within said enclosure, means connecting one end of said latches to said bus and means connecting the opposite ends of said latches to one contact of their respective mechanisms, said bus extending to the exterior of said enclosure and there carrying terminal means adapted for the connection of circuit conductors.

16. An electric circuit breaker comprising a scalable enclosure having a plurality of compartments formed by insulating formations comanism within said enclosure, means connecting one end of said latches to saidbus and means connecting the opposite ends of said latches to the movable contact surfaces of their respective mechanisms, the cooperating stationary contact surfaces being disposed on connectors having circuit conductor receiving portions at the exterior 5 of the enclosure.

JOHN G. JACKSON.

REINHOLD MUELLER. 

